The present invention relates to a unit for applying labels to a surface, and more particularly to a unit for applying labels at designated locations along the length of a moving web of material so as to mark such locations.
The production of a number of materials such as paper, films, textiles, and floor coverings, is carried out by forming such materials as elongated webs of substantial length which are thereafter segmented by cutting to yield lengths which are usable by the customer. While the character of the material along the length of the web may appear to be uniform, in many instances there will be variations along the length of such webs. These variations may arise for example in the form of slightly modified construction techniques which are intentionally introduced and/or in the form of either instantaneous or running defects within the material forming the web.
As will be appreciated by those of skill in the art, following production of the web material, the web will typically undergo an inspection process to identify the location and nature of variations along its length. Such inspection may be performed either manually and/or through use of automated equipment. One such automated system for the identification of variations along the length of a material web is believed to be available from Elbit Vision Systems which is believed to have a place of business in Tel Aviv, Israel.
Based upon the inspection of the web material produced, a listing of the variations along the length of the web may be generated. Such a listing is commonly referred to as a defect map. The map typically identifies the location, duration, and nature of the variations identified along the length of the material web. This data is typically stored in a retrievable registry format referred to by those of skill in the art as a defect album.
While the web materials which are formed are generally of extremely long length, the ultimate users of such materials oftentimes require lengths which are much shorter than the lengths formed during the production process. Moreover, the quality standards for different users may vary such that certain defects will be permissible to some users while being unacceptable to others. In recognition of the need to segment the web of material to yield shorter lengths of character and quantity as may be required by the various users, such production webs typically undergo what is referred to as a debatching process. During the debatching process the web is segmented and allocated for delivery to various customers. Such segmentation and allocation is typically carried out using the information from the map of variations along the length of the material web so as to deliver material which conforms to the product specifications of the various purchasers. The segmented lengths of material are typically placed into a roll form for delivery to the user.
As will be appreciated, in the event that the material being formed is a textile, the segmented webs of textile material which are shipped to the user may be subject to further cutting to yield panels of material which are thereafter incorporated into garments or other final structures being produced. In order to assist the users of such materials in efficiently conducting such further cutting, it is known to place removable labels at locations along the length of the material to identify the location and duration of any anomaly or other variation as may be present along the length of the material web. Such labels are typically placed in overhanging relation to the edge of the material web such that a portion of the label will protrude outwardly from the end of the roll of material shipped to the user. By way of example only, in the event that there is a running defect along some lengths of the material provided to the user, labels may be placed at the origin and the termination of the length of material affected by such running defect so as to alert the user of the material to the presence of such defect thereby permitting him or her to cut around the defect or to otherwise adjust production accordingly.
Although the use of labels to identify the location and duration of variations along the length of a material web is generally known, the actual placement of such labels at the proper location has heretofore been difficult to achieve. Such difficulty has typically arisen as a result of variations in the speed with which the material web travels during the debatching process. Moreover, the label application devices which have been previously available have generally been large, cumbersome units which are not versatile in assuming different operating configurations as may be required based on the layout and availability of space along the path of travel for the material web to be marked.
It is a general object of the present invention to provide an application unit for the precise disposition of labels at designated locations along the length of a web of material when such web of material is moving at variable rates of speed.
It is a further object of the present invention to provide an application unit for the disposition of labels at designated locations along the length of a moving web of material which application unit incorporates angular adjustment for placement along inclined portions of the conveyance path for such web of material.
According to a potentially preferred feature of the present invention, the application unit includes a label discharge mechanism which is operatively connected to a controller which actuates the label discharge mechanism according to a variable timing sequence as a function of the rate of travel of the web of material.
According to a further feature of the present invention, the application unit for applying labels at designated locations along the length of a moving web of material utilizes an articulating reversible vacuum grid as the discharge mechanism to place the label at a designated location.
According to a further feature of the present invention, the application unit preferably includes dual label discharge mechanisms each of which is independently operable from the other.
According to a further feature of the present invention, the application unit includes a label placement verification sensor to confirm proper placement and adhesion of the label.
According to one aspect of the present invention an application unit for applying labels at designated locations along the length of a moving web of material is provided. The application unit includes one or more label discharge mechanisms in the form of reversible vacuum grids which accept labels from a carrier backing for placement along the length of the moving material web. The label discharge mechanisms are actuatable in response to commands from a controller to place labels at designated locations. The controller initiates actuation of the label discharge mechanisms according to a variable timing sequence which is a function of the rate of travel of the moving web to which the label is applied. The variable timing sequence is calculated based upon the time lag between actuation of the label discharge mechanism and completion of the label placement and the amount of material which is transmitted past the label discharge mechanism during such time lag given the rate of travel of the material web. Such rate variable actuation thereby permits placement of the label at the precise location desired regardless of the actual rate of web travel.
Accordingly, the present invention provides useful advantages and alternatives over the prior art.
While the invention has been generally described and will hereafter be illustrated and more fully described in connection with certain potentially preferred embodiments, it is to be understood that the invention is in no way limited to such illustrated and described embodiments. To the contrary, it is contemplated that persons of skill in the art may make modifications to such preferred embodiments within the scope of the invention. Thus it is the intention of the applicants to cover all such alternatives and modifications as may fall within the true spirit and scope of the invention.